Graco SlimFit3 LX vs Extend2Fit Car Seats: Complete Comparison

Graco is a well-loved brand for baby gear and child safety seats, especially for its top-ranked Extend2Fit 3-in-1 convertible car seat and newer SlimFit3 LX 3-in-1 convertible car seat.

The Extend2Fit is a popular choice for parents because it’s safe, comfortable, and easy to use, but it’s too wide to fit three across in the back of most cars. The SlimFit3 LX 3-in-1 is a more compact alternative, with a narrow base and otherwise similar features to the Extend2Fit.

As a family who owns both these car seats and uses them regularly for our two children, read on for our detailed comparison of the Graco SlimFit3 LX vs Extend2Fit car seats.

Graco SlimFit3 LX vs Extend2Fit: Pros and Cons

Graco SlimFit3 LX vs Extend2Fit
Our Graco Extend2Fit on the right, with blue accents, and our SlimFit3 LX on the left, in gray

There are many features we love about both these car seats. They have undergone rigorous safety testing by Graco, they accommodate little ones from the newborn stage into young childhood, and they’re extremely easy to adjust as children grow.

From our personal experience using these two car seats, here’s what we’ve found to be the major advantages and disadvantages of each:

Advantages of the SlimFit3 LX over the Extend2Fit:

  • The 16.7-inch SlimFit3 LX is almost six inches narrower than the 22.5-inch Extend2Fit, making the SlimFit3 LX small enough to fit three across in our back seat.
  • The SlimFit3 LX is almost two pounds lighter than the Extend2Fit, making it easier to switch between cars, carry through the airport, or remove the car seat for cleaning.
  • Although the fabric padding of each car seat is machine-washable, the seat pad of the SlimFit3LX can be removed and reattached without needing to uninstall the car seat.
  • The seat back of the SlimFit3 LX incorporates breathable mesh airflow channels to help prevent kids from becoming too warm in the car.

Advantages of the Extend2Fit over the SlimFit3 LX:

  • The $250 Extend2Fit 3-in-1 is slightly more affordable than the $280 SlimFit3 LX 3-in-1.
  • The Extend2Fit allows children to ride in the rear-facing position longer, with a rear-facing weight limit of 50 pounds, compared to the SlimFit3’s rear-facing weight limit of 40 pounds.
  • The Extend2Fit also has an extendable, four-position panel that gives children more legroom and keeps them comfortable in the rear-facing position for longer as they grow.
  • A greater recline capability makes the Extend2Fit more comfortable for little ones on longer car rides, especially in cases when they’re likely to sleep.

Detailed Feature and Specification Comparison

To help in your decision between the Graco SlimFit3 LX and the Graco Extend2Fit, we’ve compiled all the similarities and differences between these car seats into one place. Read on for everything you need to know:


Graco SlimFit3 LX vs Extend2Fit

Graco, a brand with over 20 convertible car seat options, sells child safety seats that range anywhere from $100 to $500 in price. The SlimFit3 LX and the Extend2Fit 3-in-1 both fall in the middle of the range, costing about $280 and $250, respectively.

The Extend2Fit is also available as a standard convertible car seat without the “3-in-1” label for roughly $200. The tradeoff parents make for saving $50 on the more affordable Extend2Fit convertible seat is that it does not transform into a highback booster like its more expensive 3-in-1 counterpart.

Child weight range

The SlimFit3 LX and the Extend2Fit 3-in-1 have similar child weight ranges, with the Extend2Fit allowing children to ride in the rear-facing position for a longer period of time.

The SlimFit3 accommodates children from 5 to 40 pounds in the rear-facing position, while the Extend2Fit accommodates children from 4 to 50 pounds in the rear-facing position. Both car seats are appropriate for kids from 22 to 65 pounds in the front-facing position, and up to 100 pounds in highback booster mode.

One of the main reasons the Extend2Fit is so popular is that it allows children to ride in the rear-facing position — which is the safest way to ride — for longer than most competing car seats. When we were shopping for our first convertible car seat, discussions with our pediatrician and research into the safety benefits of riding rear-facing led us to choose the Extend2Fit.

Safety features

Graco SlimFit3 LX vs Extend2Fit

Both the SlimFit3 LX and the Extend2Fit meet the crash-testing requirements laid out by the United States Motor Vehicle Safety Standard (US MVSS) 213. They are also part of Graco’s “ProtectPlus Engineered” car seats, meaning that they have undergone additional collision testing to ensure their safety above and beyond what is required by the federal standard.

Using the brand’s own dedicated car seat crash testing facility, Graco uses speed and force roughly double what is required by the US MVSS 213 in each collision scenario. In addition to the front-impact crash safety testing outlined in the federal standard, Graco has ensured the safety of the Extend2Fit and the SlimFit3 LX in various side-impact, rear-impact, and rollover accidents.

Since car seat materials can become fragile and brittle in extreme hot and cold weather, Graco has also tested the integrity of both car seats after prolonged exposure to extreme temperatures.

Both car seats sport a steel-reinforced frame, adding to their safety and durability over time. The SlimFit3 LX also boasts the use of absorbent foam that makes the car seat more energy-efficient. Both convertible car seats should be discarded once they reach 10 years from their date of manufacture.

Car seat size and weight

There’s no denying that one of the major advantages of the Graco SlimFit3 LX 3-in-1 over the Extend2Fit 3-in-1 is its considerably smaller footprint. The Extend2Fit dimensions measure 19.3″ long by 22.5″ wide by 24.5″ high. The SlimFit3’s dimensions come in at 20.7″ long by 16.7″ wide by 24.5″ high.

The SlimFit3 is almost six inches narrower than the Extend2Fit. This makes a huge difference when we’re trying to maneuver the SlimFit3 into position or fit it into the car with other car seats alongside it. The SlimFit3’s narrow width is one of the key factors that makes it such an appealing car seat for parents, especially if they need to fit three car seats in the back seat.

In comparison, the Extend2Fit is wide and bulky, and it can be uncomfortable for adults to sit next to in the back seat.

The SlimFit3 is slightly lighter than the Extend2Fit, weighing only 19.2 pounds compared to 21 pounds. A lighter car seat is easier to install, easier switch from one car to the other, and easier to clean.

The lighter weight of the SlimFit3 also makes a difference for families planning to fly with their car seat. Both the SlimFit3 LX and the Extend2Fit 3-in-1 are FAA approved for use on board. When you’re walking the length of the terminal with your luggage, your toddler, and their car seat, choosing one that’s slightly smaller helps to lighten the load.


Graco SlimFit3 LX vs Extend2Fit

The SlimFit3 LX and the Extend2Fit both feature soft, thick padding throughout, with a supportive seat back, a cushioned seating pad, and spongy harness pads over the shoulders.

Graco also implements a wide, wraparound head rest on these two car seats, which is a feature that I’ve come to love. It adds extra protection and padding for the back and sides of the head, especially on bumpier rides.

The Graco SlimFit3 LX 3-in-1 has an ample, roomy seating area despite its small size. We also love the breathable mesh airflow channels along the seat back of the SlimFit3, since kids can get warm pretty quickly in the car. The Extend2Fit does not have any mesh airflow components.


Compared to other convertible car seats, we’ve found the Extend2Fit and the SlimFit3 LX to be extremely simple to adjust. It’s easy to switch between which child is riding in which car seat, and to adapt to our little ones getting taller.

Both seats have a head rest and harness that can be extended to 10 different heights with just one hand. This means we’re able to adjust the level of the shoulder straps without needing to undo and rethread the straps every time.

One of the major drawbacks of the SlimFit3 LX, and the primary reason that I prefer the Extend2Fit for long road trips, is that the seating position of the SlimFit3 is more upright. Even at the most reclined of the car seat’s four recline options, the SlimFit3 still doesn’t lean far back enough for our toddler to sleep without her head falling forward onto her chest. By comparison, the Extend2Fit’s six recline options allows it to lean farther back, and it seems to be more comfortable for longer drives when our kids are likely doze off.

Finally, the Extend2Fit incorporates an extendable, four-position panel that gives children up to five inches of additional leg room in the rear-facing position. Having children on the taller side, our family has benefitted significantly from this feature, especially since kids should ride in the rear-facing position as long as possible before switching to front-facing.


Graco SlimFit3 LX vs Extend2Fit

The installation process is similar for the Extend2Fit and the SlimFit3 LX. We can install them using our vehicle’s seatbelts or latch hardware, which is a required component of any car manufactured in 2003 or later. Graco incorporates an audible clicking sound into their latch clips, so it’s clear to us when the car seat is secured and ready for the straps to be pulled tight.

The only major difference in installing these two car seats is that, according to the Extend2Fit manual, the latch hardware should only be used for children who weigh up to 45 pounds. Once they exceed 45 pounds in weight, the vehicle’s seatbelt is the only safe way to install the Extend2Fit securely.

Care and cleaning

Any parent who’s used a car seat for more than a few days knows that having one that’s easy to clean is a must. No matter how careful we are in the car, car seats get dirty. Accidents and spills usually happen at the most inopportune times, so being able to wash the car seat materials quickly is a lifesaver.

Both the Extend2Fit and the SlimFit3 LX have removable, machine-washable seat pads. The SlimFit3’s seat pad can actually be completely removed, cleaned, and reattached without ever needing to uninstall the car seat. This is pretty clutch for situations where time is tight, or for back seats that have two or three car seats installed.

We’ve found that for more serious messes and buildup of crumbs over time, it’s best to remove the car seat from the vehicle to really get into the nooks and crannies. Fortunately, even with the Extend2Fit, removing and reattaching the seat fabric is relatively quick and headache-free.


Graco SlimFit3 LX vs Extend2Fit

Both car seats sport clean lines without busy patterns, although the SlimFit3 LX has a slightly more modern look. The car seats come in sophisticated colors, most of which are gender-neutral.

The Extend2Fit comes in several shades of black and gray, with one color option sporting pink accents and one sporting blue accents. The SlimFit3 LX comes in two tones of gray and a deep purple.


The SlimFit3 LX and the Extend2Fit both come with two cup holders. While they might seem like minor details, toddlers love cup holders, and we’ve found them to be crucial for holding drinks, snacks, and small toys, especially on longer rides.

The primary difference is that the SlimFit3 LX cup holders are removable. Taking them out allows for more space when we need to use the other back row seats or install additional car seats.

In contrast, the Extend2Fit cup holders are incorporated into the car seat in a way that requires them to be attached for the car seat to be installed. This certainly causes the car seat to occupy more space, but it also makes the Extend2Fit cup holders easier for little hands to reach and use. We like that, with the Extend2Fit, there’s no chance of toddlers removing the cup holders from the car seat during the ride.

The Final Verdict: Graco SlimFit3 LX vs Extend2Fit

Graco SlimFit3 LX vs Extend2Fit

Overall, the Graco SlimFit3 LX and the Graco Extend2Fit are two of my favorite convertible car seats. They are both safe, durable, easy to install, easy to adjust, and easy to clean. Although the SlimFit3 LX will win out for families who need to install three car seats in the back row, I do prefer the Extend2Fit for longer car rides due to its extendable rear-facing leg room panel and its greater degree of recline.

For more helpful car seat content, check out our roundup of the best FAA-approved car seats, or our detailed reviews of the Graco SlimFit3 LX 3-in-1, the Diono Radian 3QX, the Cosco Scenera, and the UPPAbaby Mesa and Nuna Pipa car seats.

*Some links in this post are affiliate links that support this site at no extra cost to you. Thanks for keeping us going!

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